Which of the following factors does NOT affect density altitude?

Density altitude is an important concept in aviation, as it directly impacts aircraft performance. It is defined as the pressure altitude adjusted for non-standard temperature. Factors affecting density altitude include altitude, temperature, and humidity.

Altitude refers to the elevation above sea level. As altitude increases, the air pressure decreases, which contributes to higher density altitudes because the air becomes less dense.

Temperature influences density altitude since warmer air expands, resulting in lower density. Higher temperatures will increase density altitude, meaning the aircraft will perform as if it is at a higher altitude.

Humidity also affects density altitude. Water vapor is less dense than the oxygen and nitrogen that make up the majority of the air. Therefore, when there is more humidity in the air, it reduces the overall density, which effectively raises the density altitude.

Conversely, the weight of the aircraft does not directly affect density altitude. Instead, it influences the aircraft’s performance characteristics, such as takeoff distance and climb rate. While heavier aircraft may perform poorly in high density altitude conditions, the aircraft's weight itself is not a factor in calculating density altitude. Thus, it stands apart from the other three factors, which directly impact the air's density.